2018 Mac Mini [8th,6C,B] + RX Vega 56 @ 32Gbps-TB3 (Sonnet Breakaway 550) + mac...
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2018 Mac Mini [8th,6C,B] + RX Vega 56 @ 32Gbps-TB3 (Sonnet Breakaway 550) + macOS 10.14.1 [Tjeu]  


Active Member
Joined: 2 years ago

System Specs

  • 2018 Mac Mini
  • six core 3,2 GHz Intel Core i7
  • Intel UHD Graphics 630
  • 512 GB SSD
  • 16 GB 2667 MHz DDR4
  • 27" BenQ BL2711U monitor 3360 x 1890 pixels, 3840 x 2160 pixels
  • 24" Dell U2412M 1200 x 1920 pixels


eGPU hardware


Installation steps

I had to build the Graphics card into the eGPU box myself, something I hadn't expected at all. Although I'm a former technician I have no experience at all with graphic cards.After connecting the two large power connectors to the video card I connected the  eGPU to my Mac mini and it didn't function. The Sonnet switched itself on and the fan was spinning after connecting the Thunderbolt cable to my Mac but that was it. I spent half the day checking and doublechecking the hardware and the connections and browsing internet for solutions. But I didn't get it to work. I didn't expect that the two other dual cables pairs with small connectors also would fit in free connectors next to the main power connections but they did.  And after that the hardware of my eGPU was recognized by macOS Mojave. What a relieve that was.


The new option 'prefer External GPU' is helpful for most of the pure graphic apps like Photoshop CC 2019 and DXO Photolab 2. I set all graphic intensive applications to use the External GPU. However, for example PanoV2r  seems to be slower in opening a spherical panorama. The majority of my photographs  are cylindrical and spherical panorama photographs which vary in size from 500MB to 6 GB.  For stitching them into panoramas I use PTGui or PanoramaStudio Pro 3 and edit them in Photoshop CC 2019 and On1 Photo Raw. I also use DXO Photolab 2, Aurora HDR Pro and Skylum Luminar for specific editing jobs. Without this eGPU it often was not a pleasure working on this huge files.  Especially Photoshop usually took minutes to finish most of the graphically  intensive operations. With the eGPU Photoshop and ON1 Photo RAW had a huge performance boost and Parallels Desktop 14  (with Windows 10 as a VM) in particular had a very huge performance boost.  Also the onboard GPU doesn’t have to claim internal memory which has a positive effect on the system performance. And in some strange way the CPU load is much less and the processor temperatures are  noticeable lower.




Mac Mini benchmark

Geekbench 4.3.1 for Mac OS X x86 (64-bit)

Single-Core Score   


Multi-Core Score    





Gigabyte Radeon RX Vega 56 Gaming OC 8GB

Intel UHD Graphics


Metal Score



OpenCL Score





Six core 3,2 GHz Intel Core i7 Mac mini 2018 with 16GB RAM and 512GB SSD - SONNET eGFX Breakaway Box 550 with Gigabyte Radeon RX Vega 56 Gaming OC 8GB - BenQ BL2711U 27" connected to Display port eGPU and Dell UltraSharp U2412M 24" connected to Thunderbolt 3 Mac mini.

2018 Mac Mini [8th,6C,B] + RX Vega 56 @ 32Gbps-TB3 (Sonnet Breakaway 550) + macOS 10.14.1 [build link]  

Trusted Member
Joined: 2 years ago

Very nice setup.  The Breakaway Box has no power issues with the VEGA GPU?

Mac mini 2018/i7/1TB/32GB RAM
Sonnet Breakaway Box 650W. Sapphire Vega 64 - (21275-03-20G card)
OWC Thunderbolt 3 14 port hub
AKiTiO Node Duo, 1 x Patriot Scorch M.2 512G SSD PCI-E 3.0 x 2 drive.

New Member
Joined: 2 years ago

Hello Tjeu,

how was installing the Vega 56? I've got the same 53mm-heigh GPU and Sonnet mentioned that 52mm is the maximum.

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.